Rationale: In an earlier study, clinically unrecognized immunodysregulation and protein-losing enteropathy were identified in nursing home residents treated with antibiotics. Those antibiotic recipients who were also treated with bismuth subsalicu\ylate had a statistically significant decreased death rate as compared to antibiotic recipients who were not concurrently treated with bismuth subsalicyalte. In addition, there was a nonsignificant tendency for the group treated with bismuth subsalicyalte to have a lower incidence of stool protein loss. The potential mechanisms by which bismuth subsalicylate might affect mortality and/or the loss of protein across the gastro-intestinal mucosa would involve: (1) the systemic anti-inflammatory effects of the salicylate moiety; and/or (2) the local protective and/or antibiotic effects of the (unabsorbed) bismuth moiety. The proposed project will provide corroboration of the results of the original study (which was halted when the increased death rate was identified in the control group), and determine whether the systemic anti- inflammatory effects of the salicylate moiety and/or the protective/antibacterial effects of the bismuth moiety underlie a decreased death rate among antibiotic recipients treated with bismuth subsalicylate and/or aspirin as compared to placebo. The specific aims of this project are to determie whether concurrent treatment of antibiotic recipients with bismuth subsalicylate or aspirin decreases the following outcome measures: (1) death rates within 7, 14, and 30 days following antibiotic prescription; (2) prevalence of protein- losing enteropathy within 7, 14, and 30 days following antibiotic precription; and (3) levels of plasma cytokines, e.g. tumor necrosis factor (TNF), interleukin-2 receptor (IL-2R), etc within 7, 14, and 30 days following antibiotic prescription. Study Design: Partially blinded, randomized, prospective comparison trial. Randomization will be done by unblocked allocation using a table of random numbers. Intervention: Bismuth subsalicylate 30 ml four times per day for 21 days (1040 mg salicylate total daily dose) vs. aspriin 325 mg three times per day for 21 days (975 mg salicylate total daily dose) vs, placebo three times per day for 21 days for antibiotic recipients enrolled within 72 hours of initiating antimicrobial therapy. Enrollees will be monitored for 30 days following the initial prescription of antibiotics.